DVSP
DVSP is a colloquial term that refers to one of Little King's Story's most famous unsolved mysteries, which pertains to the classical origin of one of the most prevalent pieces of music in the game. The abbreviation stands for "Dark Valley / Skull Plains", the two main areas in which this particular music plays, which also happen to be two of the game's most important areas. As every other main piece of music in the game has been identified, as well as many short jingles and every Tunesmith Song, it stands to reason that this piece has a classical origin as well that has simply not been discovered yet. Furthermore, several members of the development staff have confirmed that every piece of music featured in the game is classical, sans the music video by the band Bittersweet featured in the Marvelous Theater. Lending to the difficulty of identifying the piece is the fact that it's a mostly slow, ambient piece with a relatively simple melody.
A high quality upload of the music can be found here.
History
The music for Dark Valley and Skull Plains was first publicly heard during a demonstration of the game at Tokyo Game Show 2008, which ran from the 9th to the 12th of October that year. A recording of this event can be found here.
The music was first uploaded to YouTube on the 2nd of November 2009 by user Klagmar. Most of this user's uploads had discussion in their comments sections about the origins of the pieces, and the descriptions would be updated with the agreed origin. However, there was no conclusive agreement on what this piece of music could be, and thus "Aquarium" by Camille Saint-Saëns was suggested as a possible but not definite origin, based on a somewhat similar introduction. The Little King's Story Wiki also put this down as the piece's origin on the page for the game's music. When the game's community died down in the years to come, the true answer remained a mystery.
With the renaissance of the Little King's Story community starting in early 2019, a renewed interest in finding a confirmed origin for the music emerged. The community has since collaborated with several online classical music communities about its origin, including multiple posts to r/ClassicalMusic's weekly music identification thread and a post to TalkClassical.com that received over a thousand views. Aquarium has become a less favored answer and was removed from the Wiki, dismissed under the pretence that many other pieces of classical music begin with similar repeating falling notes, such as Mozart's "Masonic Funeral March" and Rachmaninov's "Danse Orientale", but like Aquarium do not continue on to sound like DVSP beyond these introductions. There are also minor aspects that bear resemblance to other pieces; a recurring trumpet tune in DVSP sounds near identical to one in Bruckner's "Symphony No. 8 in C minor", but the similarity ends there. The current consensus is also that it seems mostly likely to be a late romantic piece from the late 19th century. Composer Yutaka Minobe has never commented on the piece, and other members of the game's development staff have been unable to provide an answer when asked. The search is still ongoing.